Method for controlling a multivalent energy supply installation

ABSTRACT

A method is provided for controlling a multivalent energy supply system including at least two energy generators using at least two different energy carriers to provide heat, cold, and/or electrical energy. For each generator, a closed-loop controller controls variables of the generator. Each generator assumes one of three possible switching states: the generator must be switched on, must be switched off, or may be switched on or off. The system includes a control device for coordinatedly controlling the closed-loop controllers. The control device detects at least one request for heat and/or cold and/or electrical energy and determines whether a specific criterion is present which specifies exactly one of the three possible switching states for each generator. The control device determines target values for meeting the request depending on the request and the specific criterion and outputs the target values to the closed-loop controllers.

The present invention relates to a method of controlling a multivalentenergy supply system comprising at least two energy generators which useate least two different energy carriers to provide energy in form ofheat and/or cold and/or electrical energy. The invention further relatesto a control device for controlling a multivalent energy supply system.

A method of operating a system comprising a plurality of heat generatingmeans is known, for example, from EP 2187136 A2. The system may provideheat power using a plurality of heat generating means, wherein theallocation of the heat power to the individual heat generating means isvariable so that they can be operated close to their optimal efficiency.The allocation of power may not only be performed by means of ahigher-level boiler management system, but also be carried out bycoordinating the individual heat generating means with each other.

From the International Patent Application WO 2009/141176 A1, a mobileheating system is known which comprises a plurality of fuel-operatedheating devices which are in communication with each other via a bussystem. The heating system is configured such that, when starting theheating system, one of the heating devices is configured based onpredetermined rules as a master with respect to the control of otherheating devices connected to the bus system. The remaining heatingdevices are configured as slaves.

The European Patent Application EP 2144130 A1 discloses a groupmanagement system that can control a plurality of devices collectivelyand allows flexibly adding or changing device groups.

A hybrid heating system comprising at least one condensing boiler and atleast one non-condensing boiler is known from the International PatentApplication WO 2008/091970 A2. Switching on or off the individualboilers is carried out by a control after determining the heat load,inter alia, based on the flow in the main line of the heating system aswell as other starting criteria. The selection of the boilers is carriedout based on the ambient temperature and the operating hours of theindividual boilers.

The object of the present invention is to specify a method ofcontrolling a multivalent energy supply system which can provide animproved utilization of currently available energy resources compared tothe prior art. In particular, a method of controlling a multivalentenergy supply system is to be provided which takes into accountgenerator-specific criteria which may result, for example, from the useof different energy carriers. By taking into account generator-specificcriteria, it can also be ensured that the useful life of the energygenerators is distributed particularly uniformly, whereby a smoothoperation and a long life of the energy generators are made possible.Furthermore, a particularly safe operation of the energy supply systemcan be achieved.

It is also an object of the present invention to specify a method ofcontrolling a multivalent energy supply system which can provide animproved quality of control compared to the prior art. The quality ofcontrol describes the behavior of a control. Here, a high (or good)quality of control means that a certain required target value can beachieved in a particularly short time. A low (or poor) quality ofcontrol means that a certain required target value will only be reachedin a relatively long time. The present invention thus aims at improvingthe control of a multivalent energy supply system in such a way that thetime to reach a certain predetermined target value or to meet an energysupply request is particularly low.

In conventional control methods for a plurality of energy generators ofan energy supply system, the individual energy generators aresequentially switched on or off along a predetermined order. Switchingon the next energy generator in the order always takes place only whenthe current energy demand can no longer be met by the already switchedon energy generators. Accordingly, energy generators are switched offwhen the amount of energy provided exceeds the demand requested. Here,it can occur that an energy generator which can be switched on or offand/or controlled only very slowly blocks the switch-on operation of asubsequent energy generator in the order, so that a very long time maybe necessary to meet a demand.

In a further known control method for a plurality of energy generatorsof an energy supply system, the individual energy generators areswitched on and/or off and controlled independently of one another (inparallel). The control is thus completely uncoordinated. Restrictions orspecific characteristics of individual energy generators cannot be takeninto account in the control of the energy supply system.

The control method according to the invention aims at combining theadvantages of a sequential control with those of a parallel control ofenergy generators. For this purpose, the energy generators areclassified into groups, wherein a variable order of the energygenerators is set within a group. Furthermore, an order of groups calleda cascade may be defined, with a cascade comprising one or more groups.

Thus, a cascade is a level of classification of the energy generatorssuperordinate to groups and defines a sequential order of the energygenerators contained therein, respectively. Cascades are independentlycontrollable. Thus, multiple sequential orders of energy generatorsexecutable in parallel may be defined, for each of which differentcriteria for switching on and/or off can be set.

Individual cascades may be controlled in parallel. This ensures that aplurality of sequences controllable in parallel to each other can bedefined. As a result, the control of a multivalent energy supply systemmay respond particularly well to changing conditions. Furthermore,different specific characteristics of the energy generators may becombined with each other particularly well and switching on and/or offthe energy generators may be coordinated particularly well.

The object is achieved by specifying a method of controlling amultivalent energy supply system, wherein the multivalent energy supplysystem comprises at least two energy generators which use at least twodifferent energy carriers to provide energy in the form of heat and/orcold and/or electrical energy. Each energy generator comprises aclosed-loop controller for controlling controlled variables of theenergy generator. According to the invention, a control device detectsat least one energy supply request for at least one energy form of heatand/or cold and/or electrical energy.

Each of the energy generators can assume three possible switchingstates. Either the energy generator has to be switched on or the energygenerator has to be switched off or the energy generator may be switchedon or off. If an energy generator is in the first of the three listedswitching states, it must not be switched off. If an energy generator isin the second of the three listed switching states, it must not beswitched on. These two switching states can prevent frequent energygenerators from being frequently switched on an off. In the third of thethree listed switching states, the control device can decide whether theenergy generator should be switched on or off.

For each of the energy generators, the control device determines ifthere is an energy generator specific criterion, wherein the result ofthe determination comprises exactly one of the three possible switchingstates.

In addition, energy generator specific criteria may exist which specify,for example, minimum and maximum target value limits for the operationof the energy generator.

For each of the plurality of energy generators, the control devicedetermines target values based on the at least one energy supply requestand the energy generator specific criteria and outputs the target valuesto the closed-loop controllers. When determining the target values, thecontrol device thus takes into account whether the energy generators maybe switched on or off. For example, the control device may be configuredto check whether an energy supply request can be met by energygenerators that currently must be switched on. If additional energygenerators are required to meet the energy supply request, only thoseenergy generators that do not need to be switched off may be switchedon.

The object is also achieved by providing a control device forcontrolling a multivalent energy supply system, wherein the multivalentenergy supply system comprises at least two energy generators which useat least two different energy carriers to provide energy in the form ofheat and/or cold and/or electrical energy. Each energy generatorcomprises a closed-loop controller for controlling controlled variablesof the energy generator.

According to the invention, the control device comprises a requestdetection device for detecting at least one energy supply request for atleast one energy form heat and/or cold and/or electrical energy. Thecontrol device also comprises a criteria determination device configuredto determine, for each of the energy generators, whether an energygenerator specific criterion is present which specifies exactly one ofthe three possible switching states for the energy generator.

Furthermore, the control device comprises a target value determinationdevice for determining target values for each energy generator formeeting the at least one energy supply request based on the energygenerator specific criterion. The control device also includes a targetvalue output device for outputting the target values to the closed-loopcontrollers.

The control of a multivalent energy supply system may be particularlycomplex and usually requires a customized solution tailored to thespecific system configuration such as a programmable logic controller.Depending on the complexity of the energy supply system, the developmenteffort and the associated costs for providing a system control may bevery high. In addition, when installing a multivalent energy system, theconfiguration of a corresponding control may be very complicated andtime-consuming.

Therefore, it is an object of the invention to provide methods allowingan optimal control of a multitude of different multivalent energy supplysystems with differently structured infrastructures and differentcomponents. In addition, a control device is to be provided which canoptimally control a large number of different multivalent energy supplysystems.

The control device according to the invention may be configured to carryout the method of controlling a multivalent energy supply systemaccording to the invention. In particular, the control device maycontrol a variety of different system configurations without beingreprogrammed for each new or changed system configuration.

Controlling a multivalent energy supply system may be simplifiedaccording to the invention by defining a plurality of criteria in agraded order of priority. A criterion may represent a condition forswitching on or off an energy generator. A criterion may also set orinfluence maximum or minimum target values for energy generators.

The control device may evaluate an order of criteria of differentpriority for controlling a multivalent energy supply system. The highestpriority is given to energy generator specific criteria. An energygenerator specific criterion may be that the energy generator is given aminimum runtime. The minimum runtime may specify that the energygenerator must not be switched off. The energy generator may also begiven a minimum down time which prevents the energy generator from beingswitched on.

In addition, an energy generator specific criterion may also specifyminimum or maximum target value limits. For example, an energy generatorspecific criterion may specify a maximum volume flow (or mass flow orelectric current) through the energy generator and/or a maximum power.

Since the energy generator specific criteria should have the highestpriority, the control device must not be able to change these criteria.The control device must accept the criteria from the energy generatorsunchanged.

System specific criteria may be placed at the second highest position inthe order of criteria. These criteria are independent of the energyforms of heat, cold and electric current and may, for example, set aminimum state of charge of a buffer storage. As a result, in the case ofheat, for example, a buffer frost protection can be ensured. Inaddition, a maximum state of charge of a buffer storage may bespecified. In order to ensure system frost protection in a heatingsystem, a minimum system flow temperature may also be set. In addition,a maximum system flow temperature may also be set. Accordingly, minimumand maximum system values for electrical energy and/or cold may also bespecified. By specifying system-specific criteria, an emergencyoperation of the energy supply system can be realized.

In third position in the order of priority, energy form specificcriteria may be set. These may also be generator-specific for eachenergy form. For example, depending on an outside temperature, certainenergy generators of an energy form may be locked if this is permissiblein accordance with energy generator specific criteria. The energy formspecific criteria may, for example, be season-dependent. In this way, itmay be ensured that sufficient heat is always provided in the cold ofwinter. Furthermore, it may be ensured that always sufficient coldand/or electrical energy is provided in the summer at high outsidetemperatures. In addition, it may be specified that, at any time, aspecified minimum amount of electrical energy should be provided.

In fourth position, criteria which are evaluated per cascade may bedefined. At first, also group specific criteria may be defined. Thesemay specify whether an entire group should be switched on or off and/ormay be switched on or off. Within a group, position-specific criteriamay also be defined. Position-specific criteria may be predetermined,for example, based on switch-on integrals and/or switch-off integrals.As a result, energy generators are, for example, when performing runtimeequalization within a group, prevented from switching off immediatelyafter swapping positions to prevent a drop of a controlled variablebelow a predetermined target value. The energy generator which moves toa position further back within its group within the group due to theruntime equalization may remain switched on until the actual value ofthe corresponding controlled variable increases above a threshold valueafter a specific time.

In the context of the invention, an energy generator is “switched on” ifthe power provided by the energy generator energy exceeds apredetermined power threshold. Thus, for “switching on” an energygenerator, the power provided by the energy generator is increased untilthe power provided by the energy generator is greater than thepredetermined power threshold.

In the context to the invention, an energy generator is “switched off”if the power provided by the energy generator falls below apredetermined power threshold. For “switching off” of an energygenerator, the power provided by the energy generator is decreased untilthe energy provided by the energy generator is less than thepredetermined power threshold.

A multivalent energy supply system is an energy supply system which usesmore than one energy carrier as energy source. It comprises at least twoenergy generators, each providing a usable form of energy, such as heat,cold, mechanical energy and/or electrical energy. Heat can be provided,for example, to a hot water supply and/or a heating system and/or asprocess heat, for example for industrial applications. For transportingthe heat, a fluid carrier medium, i.e., a gas or a liquid, is usuallyused, for example water or steam.

In order to operate a multivalent energy supply system optimally, thecontrol of the energy supply system has to be carried out based on thespecific characteristics of the energy generators which depend, interalia, on the type of energy carrier used. The present invention isaimed, among other things, at combining specific characteristics ofenergy generators in a synergetic manner. In other words, the methodaccording to the invention allows optimally combining the respectivemerits of different energy carriers with each other, in particular withregard to the availability and/or energy content. This is achieved bycoordinated control of the energy generators, so that from themultivalency of the energy supply system, i.e., the use of differentenergy carriers, an advantage over monovalent energy systems using onlyone energy carrier may be obtained.

In particular, a multivalent energy supply system may use a combinationof regenerative and fossil energy carriers, so that a particularlyreliable operation of the energy supply system can be achieved, since atime-varying availability of one of the energy carriers used may becompensated by using at least one further energy carrier. In this way,the method according to the invention allows the control of the energysupply system to react to conditions that change over time.

Coordinated control of the closed-loop controllers means that thecontrol device takes into account the totality of the energy generatorsin the energy supply system when determining the target values. In thepresence of a plurality of energy supply requests for different energyforms, this may involve taking into account which energy generator canprovide which energy form(s). Further, it may be necessary for thecontrol device to determine if multiple energy generators are requiredto meet the energy supply request(s). When selecting the energygenerators to meet the energy supply request(s), the control device mayalso take into account how much time the different energy generatorsrequire to reach a particular target value and/or if restrictions on theavailability of an energy carrier utilized by the energy generators arepresent.

In order to allow a coordinated control of the closed-loop controllers,the control device may be configured to detect a plurality of specificcharacteristics of the energy generators and, if appropriate, to comparethem to one another and/or to recognize and take into accountdependencies between the energy generators. In particular, specificcharacteristics with regard to the power output of the energy generatorcan be taken into account in the control of the energy supply system.Specific power output characteristics include, among other things, amaximum power that can be provided by the energy generator and the timeit takes for the energy generator to transition from a switched-offoperating condition to an optimal operating condition.

The at least two energy generators of the multivalent energy supplysystem use at least two different energy carriers in total. As energycarriers, fossil and/or regenerative energy carriers may be used. Forexample, two or more of the following may be used: coal, natural gas,heating oil, diesel, gasoline, hydrogen, biogas, wood (for example inthe form of pellets and/or wood chips) or other types of biomass,geothermal energy, solar radiation, wind, electrical energy (forexample, electric current and/or electric voltage), long-distanceheating, mechanical energy (for example, hydropower). By using differentenergy carriers, the reliability of the energy supply may be improved,since a dependence on the availability of an energy carrier (such as thesun and/or wind) may be reduced.

The multivalent energy supply system according to the inventioncomprises at least two energy generators, each of which uses at leastone of the aforementioned energy carriers to provide energy in the formof heat, cold and/or electrical energy, for example two or more from thefollowing list which is a non-exhaustive listing: oil-fired boiler,gas-fired boiler, condensing boiler, gas engine, gas turbine, combinedheat and power plant (CHP), wood boiler, (electric) heat pump,photovoltaic system, wind turbine, solar thermal collector, fuel cell.In addition, a combined heat an energy generation may, for example, beimplemented with a Stirling engine.

The various energy generators may have very different specificcharacteristics and may accordingly have different or even conflictingrequirements during their operation in a multivalent energy supplysystem. In the following, typical specific characteristics of selectedenergy generators are described by way of example.

An oil-fired boiler or gas-fired boiler uses the fossil energy sourcesheating oil or natural gas and provides heat which is usuallytransferred to a fluid carrier medium, typically water. It can supplylarge power outputs within a short time and can be switched off quickly.Such a boiler is easy to control and may therefore be used in modulatingoperation. A boiler also allows frequent switch-on/off operations andmay therefore also be used in two stages in on/off operation. Oil-firedboilers and gas-fired boilers are thus particularly flexible in theiroperation and are often used as so-called peak-load boilers which are torespond quickly to fluctuations in energy supply requests. The overallenergy costs which take into account the costs of the energy carrieritself, as well as maintenance costs and the investment costs of theboiler, are at a medium level compared to other energy generators.

A combined heat and power plant (CHP) usually uses fossil energysources, but could also operate on biogas or hydrogen derived fromrenewable sources. It supplies heat and electrical energy (electriccurrent and/or electric voltage), is easy to control and can quickly beramped up to high power output and quickly shut down again. Unlike theboiler, however, the CHP should not be switched on or off frequently. Inorder to operate a CHP economically, it is usually used in continuousoperation. Despite the high investment costs, the combined heat andpower plant as a whole therefore has relatively low overall energycosts.

A wood boiler uses solid fuel from a renewable energy source (wood, forexample in the form of pellets or wood chips) and provides heat. It isonly moderately controllable and can only relatively slowly be ramped upto high power output or shut down again. Due to the long switchingtimes, a wood boiler should not be switched on or off frequently. Whenswitching off, for safety reasons it is usually necessary to wait untilthe fuel already in the combustion chamber is completely burnt. Whenswitching on, however, first sufficient fuel must be transported intothe combustion chamber and ignited. It causes relatively low overallenergy costs. Therefore, it is usually used as a base load boiler whichis as kept in continuous operation if possible and can meet a minimumenergy demand of an energy supply system. In order to be able to reactto fluctuations in the demanded amount of energy, a wood boiler isusually used in combination with a buffer storage which intermediatelystores the heat provided by the wood boiler when the amount of heatdemanded by the consumers is less than the amount of heat provided bythe wood boiler. If the amount of heat demanded by the consumers isgreater than the amount of heat provided by the wood boiler, first theamount of heat stored may be released from the buffer storage again.Alternatively or in addition to the buffer storage, a gas boiler isoften used together with wood boilers in an energy supply system. Thegas boiler is then turned on when the demanded amount of heat exceedsthe amount of heat available from the wood boiler and from the bufferstorage. The gas boiler is therefore used as a peak load boiler.Usually, wood boilers are operated in pairs so that at least one of thetwo wood boilers is always ready for operation.

An electric heat pump consumes electrical energy and therefore usesfossil and/or regenerative energy sources depending on which source theelectrical energy was derived from. It can provide heat and/or cold, buthas a limited temperature range. Usually, a heat pump can provide amaximum flow temperature of 60° C. It is easy to control and can quicklybe ramped up to high power output and can also be quickly shut downagain. However, it may not be switched on or off frequently. It causesrelatively low overall energy costs.

Another component that is used in many multivalent energy supply systemsis a buffer storage. The buffer storage may intermediately store energyprovided by energy generators. Depending on the energy form, a bufferstorage may be, for example, a storage for electrical energy, forexample in the form of batteries or capacitors, or a heat storage and/orcold storage, for example in the form of an insulated water tank. Inaddition, energy can also be stored in the form of mechanical energy,for example in a flywheel. A buffer storage allows at least partialdecoupling of the operation of the energy generators from the energyconsumers. As a result, the efficiency of a multivalent energy supplysystem may be improved.

According to the invention, the multivalent energy supply system may beconfigured to provide energy in the form of heat, cold and/or electricalenergy. For each energy form, at least one energy supply request may bepresent. Energy supply requests for each energy form may be detectedindependently of each other by the control device and may further beprocessed into corresponding target value requests to energy generators.For example, an energy supply request may come from a consumer, aplurality of consumers, or an external or internal device thatcoordinates requests from a plurality of consumers. For each energyform, it is also possible to define criteria for energy generators thatare assigned to the corresponding energy form. Energy supply requestsfor each energy form may be independently detected by the control deviceand further processed into corresponding target value inputs to energygenerators

Furthermore, there may be more than one energy supply request for anenergy form (e.g., heat or cold or electrical energy. For this purpose,one or more energy forms may be categorized, for example, into severalenergy sub-forms based on the connection of the respective energygenerator and/or types of consumers present in the consumer circuits.This may achieve, for example, that the energy form of heat (or cold orelectrical energy) can be provided to different consumer circuits withdifferent energy supply requests. Herein, the energy generators affectedby the energy supply request may also be connected to separate consumercircuits. Alternatively, it is possible to switch between differentconsumer circuits by means of valves, throttles and/or switches.

For the energy form of heat, for example, different energy supplyrequests may be present when different flow temperatures are requestedfor the hot water supply (drinking water) and heating and/or processheat (service water or steam).

The classification into the energy forms of heat, cold and electricalenergy may also be supplemented by other energy forms. Furthermore, anenergy form may also be subdivided into energy sub-forms depending onusage. For example, the energy form of heat may be subdivided into hotwater, thermal heat and/or hot air. The energy form of cold may besubdivided, for example, into a building cooling system (for example, anair conditioning system with fresh air supply) and a device coolingsystem (for example, a coolant for cooling machines).

Since there may be energy generators in the multivalent energy supplysystem which can simultaneously provide more than one energy form, itmay be necessary to determine under which conditions such energygenerators should be switched on or off and/or be regulated orcontrolled. The control device may prioritize certain energy forms inthe control of the energy generator, so that an energy supply requestfor a first energy form are preferably treated over an energy supplyrequest for a second energy form. The control device may also set oracquire a priority order for the energy forms. For example, the priorityorder may be set manually by a user. The control device may detect andprocess energy supply requests based on the respective energy form.

For example, a CHP supplies both heat and electrical energy (e.g.,electric current and/or electric voltage). Consequently, two differentrequests from the two energy forms may be present for a CHP. However,since the electrical energy supplied by the CHP can be fed into a publicpower grid at any time in the absence of a corresponding request of theconsumers supplied by the multivalent energy supply system, the CHP isusually used in continuous operation.

The energy form of heat includes all energy generators that can provideheat energy. In addition the control unit takes into account conditionsfor switching on and/or switching off for the energy form which arerelated to an energy supply request of heat, for example, a requestedsystem flow temperature and/or a buffer temperature. Similarly, energygenerators are assigned to the energy forms of electrical energy andcold.

Each energy generator in the energy supply system includes a closed-loopcontroller for controlling controlled variables of the energy generator.Controlled variables of an energy generator include, for example, aboiler temperature of the energy generator, a volume and/or mass flow ofa carrier medium through the energy generator, a temperature of thecarrier medium in the flow and/or the return flow of the energygenerator, a power consumption of the energy generator and/or a poweroutput of the energy generator. In an energy generator that provideselectrical energy, the controlled variables may relate to an electricalcurrent, an electrical power and/or an electrical voltage.

The closed-loop controllers are coordinated by a control device which issuperordinate to the closed-loop controllers. The control device isconfigured to detect an energy supply request for energy in the form ofheat and/or cold and/or electrical energy. An energy supply request maybe, for example, a request for a certain flow temperature or a certaintemperature in a buffer storage, in particular in a certain area of thebuffer storage, or be an electric power. For example, the energy supplyrequest may be generated by a consumer or a group of consumers and beoutput to the control device via an appropriate data communication link.

The control device is further configured to determine, for each of theenergy generators, target values for meeting the energy supply requestdepending on the particular energy carrier being used, the target valuesalso including instructions for switching on or off an energy generator.

The control device is further configured to output the target values tothe closed-loop controllers. For communicating with the closed-loopcontrollers, the control device uses a suitable data communication link.

The various energy carriers used in the energy supply system may putrequirements on the energy supply system, for example due to differentcosts and/or fluctuating availability. In order to ensure anuninterrupted operation of the energy supply system if possible, thecontrol device determines the target values for the energy generators,for example, based on the current and/or also precalculated,predetermined or estimated availability of the utilized energy carriers.

For example, the control device may be configured to operate preferredenergy generators which use, for example, particularly cost-effectiveand/or regenerative energy carriers at high or maximum power.Non-preferred energy generators which use, for example, lesscost-effective and/or fossil energy carriers and which are provided tocover the peak loads should not be used to store heat in a bufferstorage. Preferred energy generators are allowed to use the bufferstorage to realize longer runtimes or fewer switching operations.

The control device according to the invention of a multivalent energysupply system may predetermine target values for the closed-loopcontrollers of the energy generator and/or issue switching requests. Inaddition to the switching requests which determine whether an energygenerator must be switched on or off, the control device may also issuereleases which allow, but not enforce, switching on or off an energygenerator.

Switching energy generators on and off by the control device in apurposeful manner alone would not be sufficient to meet the energysupply request, because the switching alone does not define at whatmodulation level or at what temperature level the released energygenerator is to operate. Therefore, target value specifications by thecontrol device are required.

The different controlled variables of an energy supply system (forexample, system flow temperature, and buffer temperature) requireindividual target value specifications to the individual energygenerators. In addition, boundary conditions should also be taken intoaccount. These boundary conditions may include, for example, controlstrategies, predetermined preferred energy generators and/or bufferdynamics.

The selective release of energy generators is not sufficient, forexample, to control a system flow temperature and/or a buffertemperature to reach a desired level with a required power. This isbecause it is not defined by the release which power at whichtemperature level each approved energy generator should provide.Therefore, additional target value specifications are required. In amultivalent energy supply system, different energy generators withindividual generator-specific restrictions (for example, minimum andmaximum values of the power, the volume flow or the runtimes) may berepresented. In addition, the extensive configuration options allowenergy generators to work at different controlled variables (e.g.,system flow temperature, buffer state of charge). These circumstancesrequire that each energy generator receives individual target values inaddition to the release or switch request.

Preferably, each closed-loop controller of each energy generator has adefined interface to receive target values from the control device, orto make actuating variables available for achieving its control targets.The actuating variables may include: an (electric) power that the energygenerator introduces into the energy supply system, a volume or massflow (or electric current) from the energy generator into the system, anenergy generator flow temperature (an electric voltage).

The control device cannot act directly on these controlled variables,but merely outputs target values to a closed-loop controller. Theregulation of the controlled variables to the nominal values remains theresponsibility of the closed-loop controllers. Instead of a fixed targetvalue, the control device may also specify an operating range (by anupper and lower restriction or a threshold value, respectively) to aclosed-loop controller in which the controlled variables can be set bythe closed-loop controller. An operating range defined by the controldevice may accordingly be defined by one or more target values whichdefine minimum and/or maximum values for the controlled variables.Controlled variables are, for example:

A maximum thermal or electrical power (or heating power, cooling power)of the energy generator which must not be exceeded. The requirement is,for example, a percentage in relation to the physically possible maximumpower of the respective energy generator.

A minimum thermal or electrical power (or heating power, or coolingpower) of the energy generator which the power may not fall below. Therequirement is, for example, a percentage in relation to the physicallypossible maximum power of the respective energy generator.

A maximum volume flow (or mass flow or electric current) of the energygenerator flowing from or through the energy generator into the energysupply system. The requirement is, for example, a percentage in relationto the physically possible maximum flow of the respective energygenerator.

A minimum volume flow (or mass flow or electric current) of the energygenerator flowing from or through the energy generator into the energysupply system. The requirement is, for example, a percentage in relationto the physically possible maximum flow of the respective energygenerator.

A minimum and/or maximum energy generator flow target temperature orelectric voltage. The requirement is in degrees Celsius or Volt. Thespecific values that the control device sends to the closed-loopcontrollers of the energy generator are also referred to as targetvalues below.

Advantageous embodiments and developments which may be used individuallyor in combination with each other, are the subject of the dependentclaims.

The control device may be configured to detect an operation mode from apredetermined set of operation modes whereby system specific criteria,such as minimum and/or maximum values, may be set.

The operation modes may, for example, be season-dependent orweather-dependent. Thus, the control device of the energy supply systemmay, for example, be configured to determine the ambient temperature andto prevent freezing of water pipes in case of frost by setting acorrespondingly calculated minimum temperature as a target value (e.g.,for a flow temperature). Similarly, at very high ambient temperatures, amode of operation of the energy supply system may be set, in which, forexample, only those energy generators that provide electrical energyand/or cold should be operated.

Furthermore, operation modes for fault situations may be defined, sothat in the event of a fault (for example, a water pipe breakage, anelectrical short circuit or the like) an emergency operation of theenergy supply system is set.

In an emergency operation of the energy supply system, the controldevice may be configured, for example, to issue a release to allclosed-loop controllers such that all energy generators may be operatedessentially autonomously, i.e., independently of each other, and mayoptionally only be controlled by the closed-loop controllers.

A variety of threshold values, operating ranges, minimum values and/ormaximum values for system operating parameters, for example buffertemperatures and/or flow temperatures, may be stored in the controldevice for a plurality of predetermined operation modes. If the controldevice detects that one of the specified operation modes is to be set,the target values for the energy generators are determined based on thestored threshold values, operating ranges, minimum values and/or maximumvalues.

An order of switching on and/or off energy generators may be dividedinto multiple cascades, wherein each cascade may include one or moresets of energy generators. Each cascade may include group specificcriteria. In each group, position-specific criteria may be defined whichmay define specific switching specifications, releases and/or targetvalue limits depending on the position within the group.

A cascade is a level of classification of the energy generatorssuperordinate to groups and specifies a sequential order of the energygenerators or groups of energy generators contained therein,respectively. Cascades are independently controllable. Thus, multiplesequential orders of energy generators executable in parallel may bedefined, wherein different criteria for switching on and/or off may beset, respectively.

In each group, a sequence of energy generators is defined, wherein thesequence may be variable, for example, depending on controlled variablesof the energy generator. Thus, for example, runtime equalization betweenseveral energy generators of a group may be realized. The order ofswitching on and/or off energy generators within a cascade may bedetermined depending on an order of the groups and the sequences withinthe groups.

Within each cascade, it may be decided autonomously whether andaccording to which criteria energy generators should be switched onand/or off in the order. Therefore, a variety of criteria may be set foreach cascade which define, for example, thresholds depending on energysupply requests.

The cascades may be executed in parallel by the control device. As aresult, the quality of control may be significantly improved compared tomethods in which only a single linear sequence of energy generators isdefined. In addition, by executing cascades in parallel, it is possibleto prevent the switching sequence from getting stuck at an energygenerator in which a switching operation is prevented by a criterionwith higher priority.

The control device may preferably detect, from each of the closed-loopcontrollers, restrictions with respect to the controlled variables ofthe respective energy generator, wherein the restrictions relate tominimum and/or maximum values of power provided by the energy generatorand/or indicate whether the respective energy generator must be switchedon or off.

These restrictions may be generator specific restrictions. As arestriction, for example, a minimum value and/or a maximum value may bespecified which may also be equal in value. In this way, an operatingpoint can be set for the energy generator at which an energy generatoris to be operated. Such an operating point can ensure, for example, aparticularly high efficiency of the energy generator. By detecting therestrictions, it can be ensured that the control device takes intoaccount specifications by the energy generators in a coordinated mannerwhen determining the target values for meeting the energy supplyrequests. In particular, it can be avoided that the control devicedetermines a target value for an energy generator which cannot meet thistarget value due to its individual restrictions.

In addition, the control device may be configured to detect, from eachof the closed-loop controllers, specific characteristics regarding apower output of the respective energy generator which indicate how anenergy generator reacts to a change in the controlled variable. Suchspecific characteristics may represent a characteristic curve of anenergy generator, indicating, for example, what power the energygenerator outputs when a particular actuating variable is set. Thespecific characteristics may relate, in particular, to dynamicproperties of the energy generator. For example, they may describe howmuch time an energy generator needs to ramp up to full load (maximumpower output) or how long it takes to switch off the energy generator(no power output).

A specific characteristic of an energy generator may also depend on ahydraulic connection of the energy generator in the energy supplysystem. It can thus be achieved that energy generators are controlled inaccordance with their physical arrangement in the energy supply system.In this way, for example, the fulfillment of a request for a certainflow temperature may be simplified.

A specific characteristic of an energy generator according to theinvention may also be the energy form(s) provided by it. In addition,the specific characteristic may be the energy carrier used by the energygenerator and/or may depend on the type of energy carrier used.

In a preferred method, the control device may detect if there is anenergy supply request for providing heat and electrical energy present.If so, the control device determines whether one of the energygenerators can provide heat and electrical energy. If so, the controldevice determines target values for the energy generator for providingheat and electrical energy based on the energy supply request.Alternatively, the control device may select at least two energygenerators such that at least one of the energy generators provides heatand at least one other energy generator provides electrical energy.

The generator specific criteria may depend on the type of energy carrierused by the energy generator. In some cases, dynamic restrictions of anenergy generator may also depend on the fuel used. As explained above, awood boiler, for example, takes much more time to start up than a gasboiler. Other generator specific criteria may be related to theavailability or costs of the energy carrier.

For example, an energy generator using the sun as an energy sourcecannot provide energy at night. A wind turbine cannot provide energyduring a lull. In case of a heat pump, a minimum interval in which theheat pump may not be switched off or a period after a shutdown in whichthe heat pump may not switched on may be predetermined. All these andother specific characteristics may affect the operation of a multivalentenergy supply system.

Preferably, the method may comprise a step of determining whether thereis an energy supply request for more than one of the energy forms ofheat, cold, or electrical energy. Then a classification of the cascadesmay be determined based on the energy form provided by the energygenerators. The control of the energy generators then is performed bythe control device based on the specified determined classification ofthe cascades into energy forms.

The method may further comprise a step of determining whether there ismore than one energy supply request for an energy generator. If there ismore than one energy supply request for an energy generator, the controldevice may determine which of the specific energy supply requests is tobe prioritized. The target values are then determined for the one energygenerator based on the priority energy supply request.

The control device preferably comprises a device for detectingrestrictions. The restrictions may relate to minimum and/or maximumvalues of power provided by an energy generator and/or indicate whetherthe respective energy generator must be switched on or off.

The control device may further comprise a coordinating unit which isconfigured to output switching requests and/or target valuespecifications from the three energy forms to the target value outputdevice in accordance with a prioritization of the energy forms.

As already described above, an energy supply request for a particularenergy form may be given priority. The advantage of this method may bethat conflicts between conflicting energy supply requests can beavoided. Thus, a reliable operation of the energy supply system can beensured.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantageous embodiments will be described in more detail belowwith reference to an embodiment shown in the drawings, to which theinvention is not limited, however.

In the figures:

FIG. 1 shows a representation of control logic of a multivalent energysupply system according to a first embodiment.

FIG. 2 shows an illustration of control logic of a multivalent energysupply system including five energy generators for three energy formsaccording to a second embodiment.

FIG. 3 is a hydraulic diagram of a multivalent energy supply systemaccording to a third embodiment including two CHPs and two gas boilers.

FIG. 4 shows a classification of the energy generators of the thirdembodiment into energy forms, cascades and groups.

FIG. 5 is a hydraulic diagram of an energy supply system according to afourth embodiment including two wood boilers and a gas boiler.

FIG. 6 shows a classification of the energy generators of the fourthembodiment into cascades and groups.

FIG. 7 is a hydraulic diagram of a multivalent energy supply systemaccording to a fifth embodiment including a heat pump and a gas boiler.

FIG. 8 shows a classification of the energy generators of the fifthembodiment into cascades and groups.

FIG. 9 shows a hydraulic diagram of a multivalent energy supply systemaccording to a sixth exemplary embodiment including two oil boilers andtwo gas boilers.

FIG. 10 shows a classification of the energy generators of the sixthembodiment into cascades and groups.

FIG. 11 is a hydraulic diagram of a multivalent energy supply systemaccording to a seventh embodiment including two gas boilers, two CHPsand two wood boilers.

FIG. 12 shows a classification of the energy generators of the seventhembodiment into cascades and groups.

FIG. 13 is a flowchart illustrating how priorities are evaluated in amultivalent energy supply system according to an eighth embodiment

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description of a preferred embodiment of the presentinvention, like reference characters designate like or similarcomponents.

First Embodiment

FIG. 1 shows a schematic structure of a control device S for controllinga multivalent energy supply system according to a first embodimentincluding three energy generators E1-E3. The three energy generatorsE1-E3 are controlled by a respective closed-loop controller R1-R3.

Each energy generator E1-E3 can assume three possible switching states.Either the energy generator E1-E3 must be switched on, the energygenerator E1-E3 must switched off, or the energy generator E1-E3 may beswitched on or off.

The control device S also comprises a request detection device 10 whichis configured to detect at least one energy supply request EA for atleast one energy form of heat and/or cold and/or electrical energy. Theenergy supply request EA may either come from outside, for example froma plurality of consumers (not shown), and be transmitted to the requestdetection device 10 of the control device S via a suitable data line, ormay also be generated internally by a request generating device (notshown) in the control device S itself.

The control device S further comprises a target value determinationdevice 11 which is configured to determine target values SW for aplurality of energy generators E1-E3 of the multivalent energy supplysystem. The target value determination device 11 transmits the generatedtarget values SW to a target value output device 12 which outputs thetarget values SW via suitable data lines to the closed-loop controllersR1-R3 of the energy generators E1-E3.

Moreover, the control device S includes a criteria determination device14 configured to determine, for each of the energy generators E1-E3,whether an energy generator specific criterion EEK is present whichspecifies exactly one of three possible switching states for the energygenerator E1-E3. The criteria determination device 14 outputs thedetermined energy generator specific criteria EEK to the target valuedetermination device 11, so that the target values SW can be determineddepending on the energy generator specific criteria EEK.

Furthermore, the control device S includes an (optional) device 13 fordetecting restrictions. The detected restrictions may, for example,relate to minimum and/or maximum values of power provided by one of theenergy generators E1-E3. The restrictions may be detected directly fromthe energy generators E1-E3 or their closed-loop controllers R1-R3. Asuitable communication link between the energy generators E1-E3 or theirclosed-loop controllers R1-R3 and the device 13 for detectingrestrictions may serve this purpose.

Alternatively, the restrictions may be generated by the control deviceS, be predetermined by a user or be output from an external device tothe control device S.

The control device S may be configured, for example, as a microprocessorwith a CPU. The request detection device 10, the target valuedetermination device 11, the target value output device 12, the device13 for detecting restrictions and the criteria determination device 14may each be configured as separate electronic components of the controldevice S. Alternatively, the CPU of the control device S may beconfigured to take over one, several or all of the tasks of the targetvalue determination device 11, the target value output device 12, thedevice 13 for detecting restrictions and/or the criteria determinationdevice 14.

Second Embodiment

FIG. 2 shows a second exemplary embodiment of a multivalent energysupply system with five energy generators E1-E5. The control device Scomprises three control units S1-S3 and a coordinating unit K. Thecontrol units S1-S3 each detect an energy supply request EA for eachenergy form.

For example, the first control unit S1 may detect an energy supplyrequest EA in the form of a heat request, the second control unit S2 maydetect an energy supply request EA in the form of a cold request, andthe third control unit S3 may detect an energy supply request EA in theform of a request for electric energy. Since there may be energygenerators in the energy supply request which provide more than oneenergy form, such as a combined heat and power plant which provideselectrical energy and heat, the control device S may detect energysupply requests EA for various energy forms which relate to the sameenergy generator.

The coordinating unit K is configured to check the energy supplyrequests EA by the three control units S1-S3 and the target valuesdetermined therefrom for conflicts and to coordinate the use of theenergy generators accordingly. For this purpose, the individual energyforms may be given different priorities. For a CHP, for example, itwould make sense to give priority to a request for electrical energy sothat it is not switched off if there is no heat request.

The coordinating unit K is configured to regulate the interactionbetween the different energy forms F1-F3. Energy generators whichprovide multiple energy forms and which receive a switch-on request withrespect to a first energy form F1 should not be allowed to be switchedoff due to energy supply requests EA for a second energy form F2 orthird energy form F3. For this purpose, the coordinating unit K assignspriorities to the energy forms. The energy form which first issues aswitch-on request to an energy generator receives the highest priority.The energy form retains the highest priority as long as its request ispresent. If, in a calculation step, several energy forms issue aswitch-on request to an energy generator, the priority is determinedaccording to a predetermined priority order.

The coordinating unit K may also take into account that as few switchingoperations as possible should occur. In particular, the coordinatingunit K also takes into account generator-specific specifications, sincethere are energy generators which may not be switched for a certainperiod after being switched on or off. Other energy generators may beswitched on and off virtually indefinitely.

If the coordinating unit K receives a request to switch on or off anenergy generator, the coordinating unit K may perform an estimation ofthe energy demand of the different energy forms. In addition, thecoordinating unit may make an estimate of a future energy demand.Accordingly, the coordinating unit K may determine whether switchingenergy generators on or off may be avoided.

Third Embodiment

FIG. 3 shows a schematic illustration of a third embodiment of amultivalent energy supply system for providing heat and electricalenergy. FIG. 3 shows a hydraulic diagram (a schematic representation ofthe infrastructure) of the energy supply system, in which heat isreleased to a fluid carrier medium, for example water. The carriermedium transports the heat via a flow V to a consumer circuit (notshown). The flow is shown as a solid arrow which illustrates the flowdirection of the carrier medium. In the consumer circuit, a plurality ofconsumers, for example, a plurality of radiators, may be arranged.

Via a return flow R, the carrier medium flows from the consumer circuitback to the energy supply system. The return flow is shown as a dashedarrow illustrating the flow direction of the carrier medium. The carriermedium may be caused to flow, for example, by means of circulating pumpswhich may be arranged in the generator circuit, for example in theenergy generators B1, B2, G1, G2, and/or in the consumer circuit. Inaddition, valves and/or throttles and/or sensors for measuring the flowand/or the temperature in the energy generators B1, B2, G1, G2 and/or inthe flow V and/or in the return flow R may be arranged to in order tocontrol or regulate a flow through the energy generators B1, B2, G1, G2.

The energy supply system comprises two combined heat and power plants(CHPs) B1, B2 and two gas boilers G1, G2, wherein the two CHPs B1, B2are each arranged in parallel to each other between the flow V and thereturn flow R. Via the return flow R, the carrier medium coming from theconsumer side flows to the energy generators which supply heat to thecarrier medium. Via the flow V, the carrier medium flows to the consumercircuit (not shown).

A first gas boiler G1 is also arranged in parallel to the CHPs B1, B2downstream in the flow V. Further downstream in the flow V, a bufferstorage P is arranged in parallel to the first gas boiler G1 and theCHPs B1, B2. Downstream of the buffer storage P, a second gas boiler G2is arranged in series in the flow V, so that the second gas boiler G2may raise the flow temperature directly. Due to the arrangement of thesecond gas boiler G2 behind the buffer storage in the flow, it cannotinfluence the temperature of the water stored in the buffer storage.

The CHPs B1, B2 and the gas boilers G1, G2 each include a closed-loopcontroller R1, R2, R3, R4 for controlling controlled variables of theenergy generators. A control device S is connected to the closed-loopcontrollers R1, R2, R3, R4 and may periodically fetch the set controlledvariables and output target values SW to the closed-loop controllers R1,R2, R3, R4. The control logic may thus be implemented as shown in FIG.1, but with four energy generators B1, B2, G1, G2.

The control device S of the energy supply system of the embodiment maybe controlled according to specifications of a set operation mode. Thefirst gas boiler G1 should only be used when both CHPs B1, B2 arealready in operation and the heat provided by them in the flow V isinsufficient to meet an energy supply request EA, for example in theform of a required temperature in the buffer storage P or a system flowtemperature at the transition (to the right in FIG. 3) to the consumercircuit. According to the operation mode, the second gas boiler G2should only be used when both CHPs B1, B2 and the first gas boiler G1are already in operation and the heat provided is insufficient to meetthe energy supply request.

It will now be explained with reference to FIG. 4 how an order ofswitching on or off in the multivalent energy supply system isdetermined. Since the multivalent energy supply system may provide bothheat and electrical energy, two energy forms F1 (for heat) and F2 (forelectrical energy) are provided.

Among the CHPs B1, B2, runtime equalization is to take place. For thispurpose, the two CHPs B1, B2 are assigned to a group GR1. Within thegroup, the CHPs B1, B2 may exchange their positions. One criterion fordetermining at which position a CHP should be placed in the group may bethe runtime difference between the CHPs B1, B2. The runtime differenceis thus an energy generator specific criterion, however. An energygenerator specific criterion shifts with the swap of positions and thusremains with the energy generator. In order to prevent constant swappingof positions of the two CHPs B1, B2 within the group GR1, in addition, aminimum runtime difference may be set, from which on runtimeequalization may take place. The control device records the runtimes ofthe CHPs and determines the order of the CHPs depending on the recordedruntimes.

Position-specific criteria always remain tied to their position and donot move with the swap of energy generators. A position specificcriterion may, for example, be specifications as to how an energygenerator should be switched on or off in time, such as, for example, aswitch-on integral and/or a switch-off integral. Another example of aposition criterion switching off an energy generator based on a buffertemperature.

By using position criteria for switching on or off energy generators, abehavior of the energy supply system may be defined independently of therespectively energy generator placed in the position. Thus, for example,threshold values may be defined, wherein exceeding or falling belowthese causes a particular predetermined switching behavior to be carriedout. Thus, it may be specified, for example, for each position in theorder of the energy generators, if the energy generator at therespective position is to be switched off or switched on when thethreshold value is exceeded or fallen short of. It is thus possible toset the behavior of an energy supply system with a possibly unknownconfiguration in advance within certain limits, regardless of the energygenerators actually used later on.

The order in which the first gas boiler G1 and the second gas boiler G2are switched on shall be fixed. There should be no runtime equalizationbetween the gas boilers G1, G2. The reason for this may be, for example,that the first gas boiler G1 has a better degree of utilization (forexample, a condensing boiler) than the second gas boiler G2 (forexample, a low-temperature boiler). To achieve this, the two gas boilersG1, G2 are assigned to two separate groups GR2, GR3. The efficiency ofgas boilers is an example of a specific characteristic of the energygenerators.

The three groups GR1, GR2, GR3 of the first energy form F1 may beassigned to a common cascade 1. The order of the groups GR1, GR2, GR3may be fixed or variable. In order for the CHPs B1, B2 to reach as manyoperating hours as possible, the group GR1 is placed first in thecascade 1. Since the gas boiler G1 is to be preferably operated over thesecond gas boiler G2, the group GR2 with the gas boiler G1 is placedsecond in the cascade before the group GR3 including the gas boiler G21.

The control device also receives energy supply requests for a requestedelectrical energy (e.g., in the form of a current request and/or avoltage request). The CHPs B1, B2 may therefore be switched or regulatedto meet the requirements for electrical energy in addition to an energysupply request for heat. Therefore, the CHPs B1, B2 are assigned to asecond energy form F2 for electrical energy. Energy supply requests forelectrical energy and/or switching requests for energy generators thatprovide electrical energy are taken into account by the control deviceS. In this example, the CHPs would be operated to provide heat asfollows.

The first CHP B1 in the first position within the group GR1 (this mayalso be the second CHP B2 depending on the runtime equalization) isswitched on when system flow temperature drops below a required systemflow temperature. Here, the required system flow temperature is measureddownstream of the second gas boiler G2 in the flow V. When apredetermined threshold value of the temperature in the buffer storage Pwhich is measured at a layer located at the bottom in the buffer storageP is exceeded, the first CHP B1 is switched off.

The control of the second CHP B2 in the second position in the group GR1is performed in a similar manner as that of the first CHP B1. If anundershooting of the required system flow temperature is detected inspite of CHP B1 being switched on, the control device S switches on thesecond CHP B2. When a predetermined threshold value of the temperaturein the buffer storage P which is measured at a layer located in thecenter of the buffer storage P is exceeded, the control device Sswitches off the second CHP B2 again.

The gas boiler G1 is switched on when the CHPs B1 and B2 are switched onalready and the system flow temperature falls below the required systemflow temperature. Switching off the gas boiler G1 takes place when athreshold value of the temperature in the buffer storage P which ismeasured in an upper layer is exceeded.

If the first three energy generators in the cascade 1 of the energy formheat F1 are already in operation, but a system flow temperature is belowthe required system flow temperature is measured, the second gas boilerG2 is switched on. As soon as the required system flow temperature isexceeded, the control device S switches off the gas boiler G2 again.

In particular, the requirements from the energy form heat and from theenergy form electrical energy are detected in a coordinated manner andfurther processed by the control device. This corresponds to finding acompromise between the requirements of the energy form heat and theenergy form electrical energy. If the energy form heat would, forexample, request switching off a CHP, the control device S would firstcheck whether the energy form electrical energy continues to require theoperation of the CHP before the release is withdrawn. For this purpose,the control device S may be configured to estimate the energy demand ofthe relevant energy form and to make the decision on the withdrawal ofthe release dependent on whether a continued operation of the CHP isrequired. By this method, the number of switch-on and switch-offoperations may be minimized, whereby wear of the energy generator may bereduced.

According to the embodiment, a release may be issued to an energygenerator when at least one energy form requires the release of theenergy generator.

The release may then be withdrawn if no energy form requests theoperation of the energy generator anymore.

Fourth Embodiment

FIG. 5 shows a hydraulic diagram of an energy supply system according toa fourth exemplary embodiment. Similar to the third embodiment, theenergy supply system includes a buffer storage P between the flow V andreturn flow R and a gas boiler G1 in the flow V downstream of the bufferstorage P. A first wood boiler H1 and a second wood boiler H2 are eacharranged in parallel to one another and in parallel to the bufferstorage P upstream at the flow V1.

A control device S of the energy supply system according to the fourthembodiment is configured such that the wood boilers H1, H2 arepreferably used, wherein the gas boiler G1 is to cover the peak load. Asa result, the cheaper fuel wood is used for the base load (meeting aminimum energy request), while the inertia of the wood boiler H1, H2 iscompensated by the use of a gas boiler G1 which can be quickly switchedon and quickly switched off again. The gas boiler G1 may thus provide apeak load (meeting a maximum energy request).

Thus, by means of the control of the multivalent energy supply systemwhich is adapted to the specific characteristics of the energygenerator, a high quality of control may be achieved. An energy supplyrequest in the form of a required system flow temperature at thetransition to a consumer circuit (not shown) may thus be reached quicklyand may then be maintained. This can be particularly advantageous ifsensitive processes are connected on the consumer side (for exampleproduction machines).

As a further requirement for the control of the multivalent energysupply system it may be specified that a runtime equalization shouldtake place between the wood boilers. In addition, the wood boilers H1,H2 are to be operated in the upper power range, where a particularlyclean, i.e., low-emission, combustion may take place and the highestpossible efficiency is achieved. This also allows for the longestpossible operating period between maintenance operations to be achieved.

According to the prior art, usually a fixed switch-on and switch-offsequence is specified, in which no runtime equalization may take place.The first wood boiler H1 would then get much more operating hours thanthe second wood boiler H2. When a load changes (for example, by startingup the energy supply system after a standstill, such as after amaintenance or on a weekend), first the first wood boiler H1 is switchedon. However, it takes a relatively long time until a sufficient amountof heat can be supplied to meet an energy supply request. Therefore insuch a method, if the energy supply requirement is not met, first thesecond wood boiler H2 would be switched on (if necessary after apredetermined waiting time). Only after another waiting time could thegas boiler G1 also be switched on. The gas boiler G1 could supply therequired amount of heat in a relatively short time. In such a methodaccording to the prior art, it would take a relatively long time untilthe required amount of heat can be provided. In other words, the qualityof control of the energy supply system would be severely limited in sucha procedure. As a negative consequence, for example, production machinesin the consumer circuit could go into operation only after a long timedelay.

After a long warm-up period, the wood boilers H1, H2 supply heat (e.g.,after one hour) and the system flow temperature rises, as more heat isproduced than can be dissipated by the consumers or the buffer storageP. The flow temperature may rise above the required target value.Typically, the overshoot of the flow temperature above the target valueis used as a criterion for switching off the gas boiler G1. This resultsin a corresponding poor quality of control, due to which theheat-consuming production machines in the consumer circuit couldpossibly go out of operation. If the power consumed is less than the sumof the nominal power of both wood boilers H1, H2, the wood boilers H1,H2 are operated at unfavorable operating points (each at low power).

If the power consumed is less than the sum of the basic output of bothwood boilers H1, H2, the second wood boiler is taken out of operationafter a short time. A poor energy balance and negative effects ondurability and maintenance intensity of the wood boiler H1, H2 are theresult.

FIG. 6 shows how an sequence of switching on and/or off for the energygenerators of the energy supply system of the fourth exemplaryembodiment may be determined according to the invention. The woodboilers H1, H2 are combined in a group GR1, so that, as described above,a runtime equalization between the two similar energy generators H1, H2may take place.

If one were to arrange the gas boiler G1 also in the first cascade 1,namely as the last energy generator, according to the sequential orderin the cascade 1 it could be switched on only when the wood boilers H1,H2 are already in operation and the amount of energy required is notsufficient to meet the energy supply request EA. The well-controllablegas boiler G1 could therefore not be used to quickly meet peak loads.

The wood boilers H1, H2 would be switched on and off similarly to theCHPs B1, B2 in the third embodiment. However, here the gas boiler G1 isarranged in a separate cascade 2 and may thus be operated based on adifference between an actual temperature and a target temperaturemeasured at the system flow. Consequently, the gas boiler G1 may beoperated independently of the switching state of the wood boilers H1,H2, so that an improved quality of control is achieved. In order toavoid that the wood boilers H1, H2 are operated at unfavorable operatingpoints at low power, although the power of only one wood boilers H1, H2would be sufficient to cover the required power, this situation may bedetected by evaluating the power balance within the group Gr1, Acorresponding criterion for switching off the second wood boiler H2 maythereby be defined.

When starting up the energy supply system after a long period ofstandstill, the control device S recognizes that the energy supplyrequest could be met by only one wood boiler H1. Thus, the second woodboiler H2 is not released by the control device S at all. However, sincethe wood boiler H1 takes a long time to be heated, the gas boiler G1 isswitched on to supply the required amount of heat. As soon as the woodboiler H1 is sufficient to meet the request, the gas boiler G1 isswitched off again.

If the value of the required amount of energy drops so far that the flowtemperature provided by the wood boiler H1 exceeds the required systemflow temperature, the control device may temporarily store the heatsupplied in the buffer storage P. If sufficient heat is present in thebuffer storage P, then it may be used by the control device S to provideheat like an energy generator, as a result of which, in particular,rapidly occurring power fluctuations may be compensated.

Fifth Embodiment

FIG. 7 shows a hydraulic diagram of an energy supply system according toa fifth exemplary embodiment. A heat pump W1 and a gas boiler G1 arearranged in parallel to each other and in parallel to a buffer storage Pbetween the flow V and return flow R.

The heat pump W1 should preferably be used to meet a minimum energyrequest. The gas boiler G1 as a peak load boiler is intended to only tocover the difference to the required amount of heat and thus meet amaximum energy request.

In order for the heat pump W1 to be used first, according to the priorart a fixed (sequential) switch-on and switch-off sequence must bepredetermined. However, the heat pump W1 cannot go into operation ifreturn flow temperature is too high. Here, an energy generator specificcriterion could be present which requests as a switching state that theheat pump must remain switched off. Due to the fixed switch-on sequence,however, the gas boiler G1 then cannot be put into operation. Thus, therequired amount of heat cannot be delivered. This is an example of howan energy generator specific criterion EEK depending on a systemparameter (request for a return flow temperature) might prevent theenergy generator from switching on, thus blocking the activation offurther energy generators in a sequential switching sequence.

The solution to this problem according to the invention will bedescribed with reference to FIG. 8. The heat pump W1 and the gas boilerG1 are each classified into separate cascades 1 and 2. This allows thetwo energy generators W1, G1 to be switched in parallel andindependently of each other. In order for the heat pump W1 to bepreferably used, the control device S determines the target value andswitching specifications for meeting an energy supply request based onenergy generator specific criteria. In the present example, thegenerator-specific criteria relate to the type of energy generator andits dynamic characteristic. Thus, the control device S detects therestrictions of the energy generators which, for example, force ashutdown of the heat pump W1 at a too high return temperature andspecify a certain waiting time between switching operations.

Unlike shown in FIG. 8, the heat pump W1 and the gas boiler G1 couldalso be placed together in a cascade 1. If W1 would now be switched offwhen a defined temperature threshold value was exceeded, then thecontrol device S would receive a restriction of W1 that W1 can no longerbe switched on for a specific period. As a result, W1 is skipped in theswitch-on order and the next energy generator, herein the gas boiler G1,could be switched on if needed.

Sixth Embodiment

In a sixth embodiment, the energy supply system comprises two gasboilers G1, G2 and two oil boilers O1, O2 which are all arranged inparallel to each other between flow V and return flow R. For thetransfer of heat into a consumer circuit, heat transfer is provided. Ahydraulic diagram of the energy supply system according to the sixthembodiment is shown in FIG. 9.

In controlling the energy supply system, the current energy costs and/orthe availability of natural gas and heating oil should be taken intoaccount. The energy carrier with the lower energy costs shouldpreferably be used. In addition, runtime equalization should take placebetween the boilers with the same type of fuel. All boilers may beoperated in just one cascade. In order to fulfill the task formulatedabove, the gas boilers G1, G2 and the oil boilers O1, O2 are eachassigned to a separate group as shown in FIG. 10. Within each group, aruntime equalization takes place. Depending on the energy prices, theorder of the groups is selected such that the group with the lower heatproduction costs is switched on first.

Seventh Embodiment

FIG. 11 shows a hydraulic diagram of a multivalent energy supply systemaccording to a seventh exemplary embodiment. The multivalent energysupply system comprises two gas boilers G1, G2 which provide energy inthe form of heat, two CHPs B1, B2 which provide energy in the form ofheat and electric current, two wood boilers H1, H2 which provide energyin the form of heat, and a buffer storage P. In addition, a temperaturesensor T1 is arranged in the flow V which measures the system flowtemperature. In the buffer storage P three temperature sensors T2, T3,T4 are arranged, each measuring the temperature in the buffer storage P,respectively in an upper area, in a center area and in a lower area ofthe buffer storage. The gas boilers G1, G2 use natural gas from a gassupply as an energy carrier, CHPs B1, B2 use diesel from a fuel tank andthe wood boilers H1, H2 use wood pellets from a wood pellet store whichfeeds the wood boilers H1, H2 with fuel via a conveyor means.

Each of the energy generators G1, G2, B1, B2, H1, H2 includes aclosed-loop controller for controlling controlled variables of therespective energy generator G1, G2, B1, B2, H1, H2. These controlledvariables include, inter alia, a heat output and a volume flow of afluid carrier medium through the energy generators G1, G2, B1, B2, H1,H2, to which the heat is released. For controlling the volume flow, inthe energy generators G1, G2, B1, B2, H1, H2 itself or in the lines(flow V and/or return flow R) connected to the energy generators G1, G2,B1, B2, H1, H2, valves and/or throttles and/or circulating pumps arearranged. In CHPs B1, B2, the controlled variables also include anoutput electric current or electric voltage.

The control of the energy supply system by a control device S formeeting a detected energy supply request EA which, for example,determines a required system flow temperature at the measuring point T1or a buffer storage temperature at one of the three measuring points T2,T3, T4 of the buffer storage P, is performed based on the respectiveenergy carriers gas, diesel and wood used by the energy generators G1,G2, B1, B2, H1, H2. Here, wood should be used as a preferred energycarrier. Furthermore, the CHPs B1, B2 should run in continuous operationas much as possible. In order to meet the energy supply request EA, thecontrol device S determines target values SW for each of the energygenerators G1, G2, B1, B2, H1, H2 and outputs them to the closed-loopcontrollers of the energy generators G1, G2, B1, B2, H1, H2. The targetvalues SW may include specifications for controlled variables of theenergy generators G1, G2, B1, B2, H1, H2 as well as instructions forswitching on and/or switching off the energy generators G1, G2, B1, B2,H1, H2.

The control device S detects an order of switching on and/or off theenergy generators G1, G2, B1, B2, H1, H2. The order is determined bymeans of the classification of the energy generators G1, G2, B1, B2, H1,H2 into groups and cascades shown in FIG. 12. The two similar woodboilers H1, H2 are assigned to a common group GR1. As described above,runtime equalization may take place among the wood boilers H1, H2 in agroup. In a corresponding manner, the two CHPs B1, B2 are assigned tothe group GR2 and also operated with runtime equalization. The two gasboilers G1 and G2 are assigned to a group GR3. Runtime equalization mayalso take place among the gas boilers G1, G2.

The wood boilers H1, H2 and the CHPs B1, B2 are classified as preferredenergy generators, since their operation has advantages over the gasboilers G1, G2 with respect to the availability of the energy carriersused. In addition, electrical energy should be provided as continuouslyas possible in a first mode. For this purpose, the groups GR1 and GR2are assigned to a first cascade 1 as shown in FIG. 12. The order of thegroups GR1 and GR2 within the group may be based on group-specificcriteria. For example, the order may be determined according to currentfuel costs, depending on scheduled maintenance measures, or madedependent on an energy supply request for electrical energy. Inaddition, other specific characteristics of the energy generators mayalso influence the order of the groups GR1, GR2 in the cascade 1.

In a further operation mode of the multivalent energy supply system, itmay be specified to the control device S that the largest possibleamount of energy should be stored in the buffer storage P. Here, for thebuffer temperature control, a buffer temperature sensor T4 at a lowerportion of the buffer storage P is selected. The buffer targettemperature is set to, for example, 70° C. The control device S thenensures that the buffer storage P is completely charged to a temperatureof 70° C. by operating the energy generators G1, G2, B1, B2, H1, H2 toprovide the required amount of heat.

If the buffer storage P is to be loaded only approximately halfway inanother mode, a buffer temperature sensor T3 in a center area of thebuffer storage P is selected for the buffer temperature control.

In an operation mode in which buffer storage is not desired, a buffertemperature sensor T2 in an upper area of the buffer storage P isselected for the buffer temperature control. It is not necessary to seta buffer target temperature, since an energy generator flow targettemperature may be calculated from a system flow target temperature.Only as much energy as is consumed by the consumers is generated, andthe buffer storage P is not charged in this case. The system flowtemperature may be measured, for example, by a temperature sensor T1 atthe flow V.

The power output of wood boilers can be modulated only poorly. The twowood boilers H1, H2 of the embodiment may either be operated at maximumpower or be switched off. As described above, the operations ofswitching on and off are dependent on the supply or consumption of thefuel wood in the combustion chamber and thus relatively time-consumingprocesses. The wood boilers H1, H2 react only very sluggishly to achange in the controlled variable and can either deliver no power(minimum value) or maximum power (maximum value). Due to these specificcharacteristics, the wood boilers are classified into the common groupGR1.

If at least one of the wood boilers H1, H2 is in operation, it cannot beswitched off until the charged fuel is completely burned. The switchingstate of the wood boiler H1, H2 is then that the wood boiler H1, H2 mustbe switched on. The closed-loop controller of the wood boiler thennotifies the control device S that there is a restriction on the woodboiler H1 or H2 is present as an energy generator specific criterion EEKwhich specifies that the wood boiler must be switched on or may not beswitched off.

If, for example, one of the wood boilers H1, H2 has reached a maximumoperating time and to be serviced, the control device S may detect, asan energy generator specific criterion EEK, a corresponding restrictionthat the wood boiler H1 or H2 must be switched off.

Since the wood boilers H1, H2 are operated as continuously as possibledue to their sluggishness, the group GR1 including the wood boilers H1,H2 is particularly well suited for providing a minimum energy request ofthe energy supply system in the form of heat. Alternatively, the groupGR2 including the CHPs B1, B2 may be used to provide a minimum energyrequest of the energy supply system in the form of heat. The group GR2may also simultaneously provide a minimum energy request of the energysupply system in the form of electrical energy. The control device S mayselect one of the two groups GR1 and GR2 for providing the minimumenergy request based on the selected operation mode.

The gas boilers G1, G2 which are easily controllable in their poweroutput and react quickly to changes in the controlled variable, areparticularly suitable for providing a maximum energy request due tothese specific characteristics. In particular, when the amount of heatprovided by the wood boilers H1, H2 is insufficient to meet a maximumheat request, the gas boilers G1, G2 are switched on to meet therequest.

The control device S of the energy supply system of the seventhembodiment may further include an energy generator detection device 14.This detects which energy forms the energy generators G1, G2, B1, B2,H1, H2 can each provide. If an energy supply request EA forsimultaneously providing heat and electrical energy is detected by arequest detection device 10, the energy generator detection device 14determines that the CHPs B1, B2 can provide heat and electrical energyand forwards this information to a target value determination device 11of the control device S. The target value determination device 11 thendetermines target values SW for the CHPs B1, B2 for providing heat andelectrical energy dependent on the energy supply request EA. A targetvalue output device 12 outputs the target values SW to the closed-loopcontrollers of the CHPs B1, B2 via a suitable communication interface.

FIG. 12 illustrates the classification of the energy generators of theseventh embodiment into groups and cascades. In addition, an examplesystem state is shown in which the two wood boilers H1, H2 of the firstgroup GR1 are both switched on and operate at full load. The two CHPsB1, B2 of the second group GR2 are switched off. The first gas boiler G1is switched on and is operated in a modulating manner at a load of 40%of the maximum power.

Eighth Embodiment

An eighth embodiment is shown in FIG. 13. The flowchart illustrates theorder in which criteria of different priority are evaluated by thecontrol device S of a multivalent energy supply system. The large arrowindicates the direction from highest to lowest priority. The multivalentenergy supply system may have any number of energy generators.

Each of the energy generators may assume three different switchingstates: either the energy generator must be switched on, the energygenerator must be switched off, or the energy generator may be switchedon or off. Which switching state an energy generator assumes isdetermined by energy generator specific criteria EEK.

In the exemplary embodiment, energy generator-specific criteria EEK havethe highest priority. For each of a plurality of energy generators, thecontrol device S detects whether an energy generator specific criterionEEK exists. The result of the detection is one of the three possibleswitching states mentioned above. For example, a minimum runtime can bespecified to an energy generator. The minimum runtime can prevent theenergy generator from being switched off before the minimum runtime hasexpired. The minimum runtime starts after switching on the energygenerator. The energy generator may also be given a minimum down timewhich may prevent the energy generator from being switched on before theminimum down time has expired. The minimum down time begins after theenergy generator is switched off. Accordingly, further energy generatorspecific criteria EEK for an energy generator may be defined which canprevent switching on or off.

In addition, an energy generator specific criterion EEK may also specifyminimum or maximum target value limits. For example, an energygenerator-specific criterion EEK may specify a maximum volume flow of acarrier medium through the energy generator and/or a maximum power. Thiscan prevented, for example, that the energy generator is operated withtoo high a power, for example, to prevent high wear of the energygenerator and/or to operate the energy generator as efficiently aspossible.

Since the energy generator-specific criteria EEK should have the highestpriority, the control device S cannot change these criteria. The controldevice S must accept the criteria unchanged. This hierarchy may serve toprotect the energy generators.

The second highest position in the order of the criteria is taken bysystem specific criteria AK. These criteria may be defined globally forthe entire energy supply system and be independent of energy forms. Forexample, a minimum buffer temperature may be set, below which the buffertemperature may not fall. As a result, a buffer frost protection may beensured.

Another example of a system specific criterion AK is a maximum buffertemperature. By specifying a maximum buffer temperature, for example,the total energy consumption of the energy supply system may beoptimized.

In order to ensure system frost protection, a minimum system flowtemperature may also be specified. The system flow temperature may bedefined for one or more specific measuring point(s) in the flow of theenergy supply system. The minimum system flow temperature may also bedetermined dependent on an outside temperature, as system frostprotection may only be necessary if the temperature falls below acertain outside temperature. Furthermore, the system frost protectionmay only be activated in certain seasons.

In addition, a maximum system flow temperature may also be set.Accordingly, minimum and maximum system values for electrical energyand/or cold may also be specified. By specifying system specificcriteria, an emergency operation of the energy supply system may berealized. In an emergency operation, the energy generators may beoperated independently, only controlled by the closed-loop controllers.

In the case of an emergency stop, for example when a pipe breakage hasbeen detected and/or when an emergency stop switch is actuated,requirements for valves and/or pumps in the energy supply system may beoutput in addition to switch-off requests to all energy generators, sothat certain valves are closed and/or certain pumps are switched off.

For each energy form F1-F3, criteria may be defined in parallel whichare taken into account independently of each other. Within each energyform F1-F3, criteria may be defined in a hierarchical order. In thefirst position of the order of priority within an energy form F1-F3,energy form specific generator criteria EFK may be defined.

Energy form specific generator criteria EFK may be set, for example,season-dependently. For example, in the summer, the energy form of heatmay be switched off completely, or only the supply of hot water tocertain consumers may be set. Accordingly in winter, an increasedconsumption of heat may be taken into account. Similarly,season-dependent specifications may be set for the energy form of cold.Furthermore, depending on an outside temperature, certain energygenerators of an energy form may be locked, if this is permissible inaccordance with energy generator specific criteria EEK.

The energy generators of an energy form F1-F3 may be classified intocascades controllable in parallel and independently of each other.Accordingly, criteria may be defined which are evaluated per cascade.Such cascade criteria may, for example, predetermine switch-on integralsand/or switch-off integrals. In this way, for example, an energygenerator, when performing runtime equalization with another energygenerator, is prevented from immediately switching off after swappingthe switching order in order to prevent a controlled variable fromfalling below a predetermined target value. The energy generator whichshifts to a rear position within the respective switching sequence orderdue to the runtime equalization, may remain switched on until the actualvalue of the corresponding controlled variable rises above a thresholdvalue after a certain time.

Within an energy form F1-F3, a cascade coordinator KK may ensure thatthe requests from the individual cascades are combined. Thus, criteriawithin an energy form may be coordinated so that no conflictingswitching requests or target value inputs are output to the energygenerators within an energy form F1-F3.

In the next position, the coordinating unit K coordinates the respectivecriteria or switching requests and target value specifications from thethree energy forms F1-F3. Here, the coordinating unit K may solveconflicts between the switching requests and target value specificationsfrom the three energy forms F1-F3 in accordance with a prioritization ofthe energy forms F1-F3.

According to the order of priorities described in this embodiment, thecontrol device S may determine which energy generators are available tomeet an energy supply request EA. Furthermore, restrictions onindividual energy generators or energy forms F1-F3 with differentpriorities may be taken into account. By specifying the criteria, aplurality of operating modes and/or operating states of a multivalentenergy supply system may be determined based on a plurality of operatingparameters, energy supply requests EA and/or external conditions. Themethod according to the invention may thus enable a particularly safeand efficient operation of a multivalent energy supply system

The features disclosed in the foregoing description, the claims and thedrawings may be of importance for the realization of the invention inits various forms both individually and in any combination.

LIST OF REFERENCE SYMBOLS

-   10 request detection device-   11 target value determination device-   12 target value output device-   13 device for detecting restrictions-   14 criteria determination device-   V flow-   R return flow-   S control device-   S1 first control unit-   S2 second control unit-   S3 third control unit-   K coordinating unit-   P buffer storage-   R1 first closed-loop controller-   R2 second closed-loop controller-   R3 third closed-loop controller-   R4 fourth closed-loop controller-   R5 fifth closed-loop controller-   E1 first energy generator-   E2 second energy generator-   E3 third energy generator-   E4 fourth energy generator-   E5 fifth energy generator-   G1 first gas boiler-   G2 second gas boiler-   O1 first oil boiler-   O2 second oil boiler-   B1 first CHP-   B2 second CHP-   H1 first wood boiler-   H2 second wood boiler-   W1 heat pump-   GR1 first group-   GR2 second group-   GR3 third group-   F1 first energy form (heat)-   F2 second energy form (electrical energy)-   F3 third energy form (cold)-   EEK energy generator specific criteria-   AK system specific criteria-   EFK energy form specific generator criteria-   KK cascade coordinator

The invention claimed is:
 1. A method of controlling a multivalentenergy supply system, wherein the energy supply system comprises atleast: at least two energy generators (E1-E5, B1, B2, G1, G2, H1, H2,O1, O2, W1) which use at least two different energy carriers to provideat least two energy forms selected from the group consisting of heat,cold and electrical energy; for each energy generator, a closed-loopcontroller (R1-R5) for controlling controlled variables of the energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1); and wherein eachenergy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) can assumethree possible switching states: the energy generator (E1-E5, B1, B2,G1, G2, H1, H2, O1, O2, W1) must be switched on, the energy generator(E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) must be switched off, theenergy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) may beswitched on or off; a control device (S) for coordinatedly controllingthe closed-loop controllers (R1-R5), wherein the control device (S)carries out the following method steps: detecting at least one energysupply request (EA) for at least two energy forms selected from thegroup consisting of heat, cold and electrical energy; for each of theenergy generators (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1),determining whether there is an energy generator specific criterion(EEK) which specifies exactly one of the three possible switching statesfor the energy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1);determining whether there is more than one energy supply request (EA)for an energy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1); ifthere is more than one energy supply request (EA) for an energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1): determining whichof the energy supply requests (EA) should be treated as a priority; foreach energy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1),determining target values (SW) for meeting the at least one energysupply request (EA) based on the energy supply request which is treatedas a priority (EA) and the energy generator specific criterion (EEK);and outputting the target values (SW) to the closed-loop controllers(R1-R5).
 2. The method according to claim 1, wherein the control device(S) further detects an order of switching on and/or off the energygenerators (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1), and whereindetermining the target values (SW) is performed depending on the order.3. The method according to claim 1, wherein at least one energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) is used to meet aminimum energy request.
 4. The method according to claim 1, wherein atleast one energy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1)is used to meet a maximum energy request.
 5. The method according toclaim 1, wherein the control device (S) further carries out the stepsof: detecting, from each of the closed-loop controllers (R1-R5),restrictions on the controlled variables of the respective energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) from each of theclosed-loop controllers (R1-R5), wherein the restrictions relate tominimum and/or maximum values of a power provided by the energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) and/or indicatewhether the respective energy generator (E1-E5, B1, B2, G1, G2, H1, H2,O1, O2, W1) must be switched on or off; detecting, from each of theclosed-loop controllers (R1-R5), specific characteristics regarding apower output of the respective energy generator (E1-E5, B1, B2, G1, G2,H1, H2, O1, O2, W1) which indicate how an energy generator (E1-E5, B1,B2, G1, G2, H1, H2, O1, O2, W1) responds to a change in controlledvariables; determining an order of switching on and/or switching off theenergy generators (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) based onthe restrictions and/or the specific characteristics of the energygenerators (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1); determiningtarget values for each energy generator (E1-E5, B1, B2, G1, G2, H1, H2,O1, O2, W1) for meeting the at least one energy supply request (EA)depending on the order of switching on and/or off.
 6. The methodaccording to claim 1, wherein the control device (S) further carries outthe steps of: detecting whether there is an energy supply request (EA)for providing heat and electrical energy; determining whether one of theenergy generators (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) canprovide heat and electrical energy; determining target values (SW) forthe energy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) forproviding heat and electrical energy based on the at least one energysupply request (EA).
 7. A control device (S) for controlling amultivalent energy supply system, wherein the multivalent energy supplysystem comprises at least: at least two energy generators (E1-E5, B1,B2, G1, G2, H1, H2, O1, O2, W1) which use at least two different energycarriers to provide at least two energy forms selected from the groupconsisting of heat, cold and electrical energy; and for each energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1), a closed-loopcontroller (R1-R5) for controlling controlled variables of the energygenerator; wherein each energy generator (E1-E5, B1, B2, G1, G2, H1, H2,O1, O2, W1) can assume three possible switching states: the energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1) must be switchedon, the energy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1)must be switched off, the energy generator (E1-E5, B1, B2, G1, G2, H1,H2, O1, O2, W1) may be switched on or off; wherein the control device(S) comprises: a request detection device (10) for detecting at leastone energy supply request (EA) for at least two energy forms (F1-F3)selected from the group consisting of heat, cold and electrical energy;a criteria determination device (14) configured to determine, for eachof the energy generators (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1),whether there is an energy generator specific criterion (EEK) whichspecifies exactly one of the three possible switching states for theenergy generator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1); a targetvalue determination device (11) configured to determine, for each energygenerator (E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1), target values(SW) for meeting the energy supply request (EA) based on the energygenerator specific criterion (EEK): a target value output device (12)for outputting the target values (SW) to the closed-loop controllers(R1-R5); and a coordinating unit (K) configured to output switchingrequests and/or target value specifications from the energy forms(F1-F3) heat, cold, and electrical energy to the target value outputdevice (12) according to a prioritization of the energy forms (F1-F3)heat, cold, and electrical energy.
 8. The control device (S) accordingto claim 7, wherein the control device (S) further comprises a device(13) for detecting restrictions, wherein the restrictions relate tominimum and/or maximum values of power provided by an energy generator(E1-E5, B1, B2, G1, G2, H1, H2, O1, O2, W1).